1. Field of the Invention
The present invention relates to a display device, and more particularly to a display device adapted to minimize brightness deterioration and motion blurring in a motion picture, and a driving method thereof.
2. Description of the Related Art
In a hold type display device, such as a liquid crystal display (LCD) or an organic light emitting diode (OLED), a blurring phenomenon may occur. The blurring phenomenon is characterized in that a screen is unclear and blurry when a motion picture is playing. This is caused because a data voltage is maintained in a pixel. This will be explained in conjunction with FIGS. 1 and 2 that represent data characteristics of an LCD device and a cathode ray tube (CRT).
A CRT device is an impulse type display device. The data characteristic of the CRT, as shown in FIG. 1, displays data by emitting phosphorus light for a very short time in an early stage of one field period. Later stages of the field period are pause intervals. In contrast, in the LCD device, as shown in FIG. 2, data is received during a scanning period of one field period when a scan high voltage is supplied. The data is maintained in a non-scanning period for the majority of the field period.
Accordingly, a perceived image in a motion picture is clearly displayed in the CRT. In contrast, in the LCD device, the motion picture display is blurred by a blurring phenomenon caused because a data voltage is maintained in a pixel. The difference between the actual image and the perceived image results from an integration effect of the image which temporarily lasts in an eye of a viewer after movement on the display. Accordingly, even though the response speed of the LCD device is fast, an observer sees a blurred screen because of a disparity between the movement of the eye and the static image of each frame.
To decrease the motion picture blurring of the LCD device of the related art, a method has been proposed in which a holding time is reduced and black data is inserted for a portion of the frame period, as shown in FIG. 3.
This motion blurring relaxation method reduces the holding time of frame data D1-D5, shown in FIG. 4, within each frame and inserts black data B1-B5, as shown in FIG. 5. That is, for each frame that one of the frame data D1-D5 is inserted into, one of a black data B1-B5 is inserted. Thereby, an LCD device is driven by a pseudo-impulse that relaxes the motion blurring phenomenon. Accordingly, as shown in FIG. 3, because of the reduced holding time, the gray level of the input data is expressed for about 60% of each frame while the gray level of the inserted black data B1-B5 is expressed for about 40% of each frame.
However, the motion blurring problem can only be resolved to a certain extent by the motion blurring relaxation method shown in FIGS. 3 and 5. Because in this method, the data holding time of frame data D1-D5 of each frame is reduced and black data B1-B5 is inserted, the brightness BDI of the picture is remarkably decreased, as shown in FIG. 6.